Development of Process for Recovery Metal Carbide Powder from Cemented Tungsten Carbide Scraps

Abstract

The recycling of materials is the recovered process and the important approach for sustainable development. This research is to study recycling tungsten carbides from cemented carbide scraps by extracting the dissolved of binder phase, and to study the un-dissolved substrate which stayed condition and size in WC particles. The experiment of this research starts in laboratory with electrolysis, is found that the appropriate operating potential is 0.20-1.40 volts, at 30-80 oc, treated in 1N-7N HCl concentrations aqueous solution as well as the movement of solution and specimens had an effect on capacity of dissolution. Additionally, these factors are affected to purity and passivation of WC particles. According to the above experiment, it leads to design and create the semi-automatic cemented dissolution machine with electrolysis. This machine can contain the scraps up to 2.5 kilograms, in rev 0-25 rpm (revolutions per minute), at electric current 0-50 ampere, in electric voltage 0-15 volts. Its flowing process can be 15 lpm (litre per minute) and minute) and temperature is up to 90 oc. Furthermore, there are the relative WC power invention processes included residues, washing, leaching, ball milling, drying, screening, and quality examination. The result of developed machine is capacity of tungsten carbide production is in the range 16-50 gram/hour, the obtained powder is 97.49% of tungsten carbide (WC powder), which contained a few amount of cobalt. However, the dissolution of cemented carbides with this machine can be selected the optimized factors to produce tungsten carbide (WC) to purify more than 99%, ball milled them in the most suitable size and particle sized distribution between 0.30-20.00 μm. Afterwards, combining cobalt 15% (WC-15%Co) and producing to cemented carbides, insert tools, rectangle as SNMG standard 120408, it appears that insert tools has a hardness not less than 1,430 HV, density not less than 14.10 g/cm³. In the other hands, the production of tungsten carbides with advanced technology of dissolution machine and manufacturing machine to produce purely tungsten carbides powder has been required an investment charge of new research and development more than 9,481,888 baht.